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Fried M.,Res Institute For Technical Physics And Materials Science Mfa | Juhasz G.,Res Institute For Technical Physics And Materials Science Mfa | Major C.,Res Institute For Technical Physics And Materials Science Mfa | Petrik P.,Res Institute For Technical Physics And Materials Science Mfa | And 3 more authors.
Thin Solid Films | Year: 2011

Our aim was to make possible to use spectroscopic ellipsometry for mapping purposes during one measuring cycle (minimum one rotation period of polarizer or analyzer) on many sample points. Our new technique uses non-collimated (non-parallel, mostly diffuse) illumination with an angle of incidence sensitive pinhole camera detector system and it works as an unusual kind of imaging ellipsometry. Adding multicolour supplemets, it provides spectral (a few wavelengths on a 2D image or a full spectrum along a line) information from rapid measurements of many points on a large (several dm2) area. This technique can be expanded by upscaling the geometry (upscaling the dimensions of the instrument, and characteristic imaging parameters such as focal lengths, distances, etc.). The lateral resolution is limited by the minimum resolved-angle determined by the detector system, mainly by the diameter of the pinhole. (The diameter of the pinhole is a compromise between the light intensity and the lateral resolution.) Small-aperture (25 mm diameter) polarizers are incorporated into both the polarization state generator (PSG) and polarization state detection (PSD) components of the instrument. The detection is almost without background because the pinhole serves as a filter against the scattered light. One rapid measuring cycle (less than 10 s) is enough to determine the polarization state at all the points inside the illuminated area. The collected data can be processed very fast (seconds) providing nearly real-time thicknesses and/or refractive index maps over many points of the sample surface even in the case of multilayer samples. The speed of the measuring system makes it suitable for using even on production lines. The necessary (in each sample-point different) angle-of-incidence and the mirror-effect calibration are made via well-known and optimized structures such as silicon/silicon-dioxide samples. The precision is suitable for detecting sub-nanometer thickness and a refractive index change of 0.01. The method can be used for mapping and quality control in the case of large area solar cell table production lines even in a vacuum chamber with 5-10 mm lateral resolution. © 2010 Elsevier B.V. All rights reserved. Source

Fried M.,Res Institute For Technical Physics And Materials Science Mfa | Juhasz G.,Res Institute For Technical Physics And Materials Science Mfa | Major C.,Res Institute For Technical Physics And Materials Science Mfa | Nemeth A.,University of Toledo | And 5 more authors.
Materials Research Society Symposium Proceedings | Year: 2012

We have developed a prototype spectroscopic ellipsometer for imaging/mapping purposes requiring only one measurement cycle (one rotation period of a polarizer or analyzer) for the acquisition of a two-dimensional array of data points. Our new measurement technique serves as a novel form of imaging ellipsometry, using a divergent (uncollimated, diffuse) source system and a detection system consisting of an angle-of-incidence-sensitive pinhole camera. By incorporating broad-band sources and wavelength dispersion optics, the instrument provides continuous high-resolution spectra along a line image of the sample surface. As a result, information on multilayer photovoltaics stacks can be obtained over large areas (several dm 2) at high speed. The technique can be expanded to even larger areas by scaling-up the optical geometry. The spatial resolution of the line image is limited by the minimum resolved-angle as determined by the detection system. Small-aperture polarizers (25 mm diameter) are incorporated into the instrument, which reduces its cost. Demonstration mapping measurements have been performed ex situ on a multilayer sample deposited on a polymer substrate, including an intentionally graded 80-350 nm thick hydrogenated amorphous silicon (a-Si:H) layer and an intended uniform 400-500 nm thick transparent conducting ZnO:Al layer, both on opaque silver. Alternative commercial instruments for ex situ SE mapping must translate the sample in two dimensions. Even a 15 x 15 cm 2 sample requires > 200 measurements with cm-resolution and at least 15 min. By collecting ex situ data in parallel along one dimension through imaging, the divergent-beam system can measure with similar spatial resolution in < 2 min. In situ measurements on both roll-to-roll polymer and rigid glass will be possible in the future. © 2011 Materials Research Society. Source

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